This probe works on the back of the SkimDB feed follower. Modules stored in the feed
collection will be checked against each listed registry/mirror. The lag is
determined from the latest known update time for each module. The difference is
calculated in milliseconds. Only modules that are lagging, e.g. have a difference > 0
will be included in the statistics.

If you like to design a custom probe, note that the following methods should be
available on the API of the probe. The parameters will be provided
from the main Collector instance. In addition to that fusing is available to
create read-only properties on the probe.

To aquire a predefined Probe constructor the factory method Collector.create
can be used. After add all API methods to the provided constructor. Make sure that
the time schedule specifications are compatible with node-schedule.